linux-kernel - [PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

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Message-ID: <7cde412f8b057ea13a646fb166b1ca023f6a5031.1755098819.git.thomas.lendacky@amd.com>
Date: Wed, 13 Aug 2025 10:26:59 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: <linux-kernel@...r.kernel.org>, <x86@...nel.org>
CC: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
	Michael Roth <michael.roth@....com>, Joerg Roedel <Joerg.Roedel@....com>
Subject: [PATCH] x86/sev: Ensure SVSM reserved fields are initialized to zero

In order to support future versions of the SVSM_CORE_PVALIDATE call,
all reserved fields within a PVALIDATE entry must be set to zero as an
SVSM should be ensuring all reserved fields are zero in order to support
future usage of reserved areas based on the protocol version.

Fixes: fcd042e86422 ("x86/sev: Perform PVALIDATE using the SVSM when not at VMPL0")
Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
---
 arch/x86/boot/startup/sev-shared.c | 1 +
 arch/x86/coco/sev/core.c           | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
index ac7dfd21ddd4..a34cd19796f9 100644
--- a/arch/x86/boot/startup/sev-shared.c
+++ b/arch/x86/boot/startup/sev-shared.c
@@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
 	pc->entry[0].page_size = RMP_PG_SIZE_4K;
 	pc->entry[0].action    = validate;
 	pc->entry[0].ignore_cf = 0;
+	pc->entry[0].rsvd      = 0;
 	pc->entry[0].pfn       = paddr >> PAGE_SHIFT;
 
 	/* Protocol 0, Call ID 1 */
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index 400a6ab75d45..14ef5908fb27 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
 		pe->page_size = RMP_PG_SIZE_4K;
 		pe->action    = action;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = pfn;
 
 		pe++;
@@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
 		pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
 		pe->action    = e->operation == SNP_PAGE_STATE_PRIVATE;
 		pe->ignore_cf = 0;
+		pe->rsvd      = 0;
 		pe->pfn       = e->gfn;
 
 		pe++;

base-commit: 4c699535a3d483562354432a945a035f15dfceeb
-- 
2.46.2